Implement the IWsdlImportExtension interface to control the mapping between WSDL and ServiceEndpoint and ContractDescription objects, especially when reading custom WSDL extensions to modify your contract or endpoint information. Then attach your custom IWsdlImportExtension object to a WsdlImporter either programmatically or by using an application configuration file. You can also attach your custom IWsdlImportExtension object to the internal WsdlImporter used by the Service Model Metadata Utility Tool (Svcutil.exe) using an application configuration file.